Line an 8x8-inch square baking pan with foil or parchment paper. Set aside.
Mix together the Biscoff spread, icing sugar, and butter until fully combined. Press the mixture into the prepared pan.
For the Chocolate Layer
Add the chocolate to a microwave-safe bowl, and heat in 30 second intervals, stirring after each one, until melted and smooth. Pour over the Biscoff layer, and spread out evenly.
Refrigerate until set - about 2 - 4 hours.
Video
Notes
Bars stay fresh stored in an airtight container in the fridge for up to 2 weeks. Serve chilled. They also freeze well for up to 3 months. Thaw overnight in the fridge.